Method of scouring cellulosic materials



Patented Dec. 30, 1947 METHOD OF SCOURING CELLULOSIC MATERIALS Hans 0.Kauffmann, Eggertsville, and Robert L. McEwen, Edward S. Shanley, andJohn R.

Hopkins, Buffalo, N. Y., assignors to Buffalo Electro-Chemical Company,Inc., Buffalo, N. Y.

No Drawing. Application April 24, 1940, Serial No. 331,438

7 Claims.

The present invention relates to a method of treating goods made offibers of vegetable origin whereby the goods are prepared so that theymay be more readily acted upon. by conventional bleaching agents. Moreparticularly, the present invention relates to a preliminary treatmentprior to bleaching which includes the padding and steeping of gray goodswith an aqueous solution of an alkali.

Heretofore, prior to the treatment of goods with bleaching agents, orsolutions containing such agents, the gray goods were preliminarilytreated with hot circulating alkali solutions in order to remove certainwaxy and resinous constituents of the cellulosic fiber that rendered itnon-absorbent and which contribute to the natural dark color. Ingeneral, the fibers were scoured by treating the same in a hotcirculating solution of caustic soda or the like, or equivalent alkali.The

goods were heated for a considerable period of time in this hotcirculating alkali until substantially all of the waxy fiber coating hadbeen eliminated and the fiber rendered soft and absorbent. The boilingwas performed for considerable periods of time, say, from 8 to 20 hourseither in open kiers or in closed kiers under pressure.

' Many disadvantages accompany these so-called caustic boils.Forinstance, the goods after treatment are often uneven in physical andchemical character, such as absorbency, tensile strength, softness, andthe like. Unless great care be taken in packing the goods in the kier,channeling of the circulating solution is likely to occur wherebygreater contact with the solution is to be had at certain points than atothers. Furthermore, as the waxy material is eliminated, more and morescum collects in the solution, is carried by the solution and may attimes deposit on the goods with the production of spots. Furthermore,the goods are quite likely to be stained with rust and other marks fromthe kier, particularly if the boil is performed under pressure.

It is an object of the present invention to soften and loosen and tosubstantially remove a considerable portion of the waxy materialsurround ing the cotton fiber, and also to soften, loosen andsubstantially absorb any motes that may be present in the goods beingtreated.

It is a further object of the invention to provide a treating methodpreliminary to bleaching treatments for cellulosic fiber whereinconsiderable saving is effected in steam consumption in the preliminarytreatment of the gray goods.

In accordance with the present invention, gray goods are padded with anaqueous solution of an alkali so that the goods contain from 50 to 200%of the solution, based on the weight of the dry goods. The goods sopadded are then permitted to stand in this soaked, padded or dampcondition until the waxy foreign matters of the fibers and any motes aresoftened and substantially removed or are changed to a condition wherethey are readily removable and then heated under conditions wheresubstantial evaporation of moisture is prevented and the goods thusmaintained in the damp condition. In general, the steeping of the graygoods padded with the alkali will require from 4 to 20 hours, more orless, and will depend to a large extent upon the type of goods beingtreated, whether heavy goods or light goods, the quantity of alkali inthe padding solution and the temperature of the steep.

After the waxy material in the cellulosic fibers has been softened andloosened and changed to a form where it is readily removable, the goodsare heated, as, for instance, by steaming for a short period of time,say from 30 seconds to 30 minutes. ishes the alkali treatment and placesthe goods in excellent condition for bleaching.

The steep with the alkali will normally be effected at room temperatureor temperatures somewhat removed from room temperature. For purposes ofimpregnating the goods with the alkali solution any conventionalprocedure may be employed. In general the preferred procedure will be torun the goods through the alkali solution, the temperature of which maybe room temperature 0r temperatures somewhat above room temperature.After uniformly wetting the goods in this manner, excess solution issqueezed out and the so padded goods then laid down in this dampcondition (containing from 50% to 200% of the solution, based on weightof goods) and permitted to steep. This steeping is continued for from 4to 20 hours or until the waxy matters are readily removable or the motessoftened and loosened, after which time the goods are steamed and washedwith water.

Although caustic alkali is preferred in making up the alkali solution,other generally used alkali may be substituted or added therefor orthereto, for instance, sodium carbonate, trisodium phosphate, sodiumsilicate, lime, and'the like. The amount of alkali in the paddingsolution should be relatively high. It may be mentioned that causticsoda is the alkali preferred and in general the alkali would be fromabout 15 to 60 grams per liter NaOH, it being understood that for heavyducks and drills larger quantities of This steaming softens the goods,finalkali will be required to produce the desired effect than arenecessary on lighter types of goods. In general, 25 to 40 grams NaOH perliter will be found a satisfactory concentration for most cotton goods;sodium silicate may be mixed advantageously with the caustic soda,

After the lay down and steep, the goods are heated rapidly underconditions where excessive evaporation of water from the goods isprevented. In general, this heating is effected by steaming the goods,that is to say, the goods are placed in" an atmosphere of steam or,where the goods are in a heavy condition, steam is passeddirectlythrough the goods in order to heat al l p qntiens thereof evenlyto obtain the efi eet on the wax and motes desired. In general, thissteaming is carried out for relatively short periods off-time, althoughit will be understood that steaming-may be required for longer periodsof time on. heavier goods than is required on light goods.

after being steamed the goods are passed into a Washer and washed toremove the alkali and to remove the waxy materials and the motes. Thewash water may be either hot; or cold andmay contain soap or otherpenetrants After being treated as above described, the goods are inexcellent condition for treatment with bleaching agents.

What is claimed is:

1. The method of treating fibers of vegetable origin prior to bleachingthe same which comprises impregnating the fibers with sufiicient of asolution of an alkali to render the fibers damp, permitting the dampenedimpregnated goods to a d nt e mews r so tened. a d. ar e re. h su ec n te fib r t l c nt n n solution of alkali to the action of steam 2, Themethod of treating fibers of; vegetable originp ior to bleaching thesame which com- Rr ses m e natin t e b r t suffigint asolution of analkali to render thefibers darhp, permitting the dampened impregnatedgoods to an nt ili mew a e ened. an qs a d. and thenheating the fibersstill containing alkali under conditions where substantial evaporationof moisture from, the fibers is prevented 3. The method of treatingfibers of vegetable Qrigin P3 ch n h? S li ih m.- prises impregnatingthe fibers with suificient of a solution containing an, alkaliin amountequivalent to about to 60 grams NaOH per liter to render the fibers dampand; permitting the dampenecl impregnated goods to stand until the motesare softened and loosened and then subjecting the fibers containingalkali to theaction of steam."

4. The method of treating fibers of vegetable origin prior to bleachingthe same which comprises impregnating the fibers With sufficient oi anaqueous solution containing to 40 grams NaOI-I- per liter to. renderthefibers damp and permitting the dampened impregnated goods to stand untilthe motes are softened and loosened and then subjecting the fiberscontaining alkali to the action of steam.

5. The method of treating fibers of vegetable origin which comprisesimpregnating the fibers with suificient of a solution of an alkali torender the fibers damp, permitting the so impregnated goods to steep formore than four hours, thereafter steaming the fibers impregnated withalkali for a short period of time and then treating the fibers with ableaching solution to bleach the same.

6, The method of treating fibers of vegetable origin which comprisesimpregnating the fibers with sufiicient of an aqueous solutioncontaining alkali equivalent to at least 15 grams NaOH per liter torender the fibers damp, permitting the so dampened impregnated fibers tosteep for more than four hours, and thereafter steaming the fibersimpregnated with alkali for a short period of time.

7, The method of treating fibers of vegetable origin which comprisesimpregnating the fibers with sufi cient of an aqueous solutioncontaining caustic soda and sodium silicate to'render the fibers damp,permitting the s -impregnated fibers to steep for'more than four hours,thereafter steaming the fibers impregnated with alkali for a shortperiod of time and then washing the same.

HANS O. KAUF'FMANN. ROBERT L. MCEWEN. EDWARD S. SHANLEY. JOHN R.HOPKINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 674,759 Cross May 21, 1901333,875 Mather Jan. 5, 1886, 395,55 Drown, Jan. 22, 1839 2,107,297Kauffmann Feb. 8, 193.8, 2,220,682 Kauffmann Nov. 5, 1949. 1,515,691Marsden T Nov. 18, 19 2 1 2,226,162 Dubeau Dec. 24, 194 22,67, 18 m l De3 .9

FOREIGN PAT NTs Number Country Date 13,867 Great Britain 1904 351,217Great Britain June 25, 1931 20,656 Great Britain 1911 289,742 GermanyJan. 15, 1916:

OTHER REFERENCES Matthews, Bleaching and Related Processes, Chem. Cat,(30., N. Y., 1921, pp. 270-271.

Haller et al., Chemische Technologie der Baumwolle, Julius Springer,Berlin, 1928, pp 24, 25.

Heerman, Enzyklopadie oler Textilchemischen Technologie, JuliusSpringer, Berlin, 1930, pp. to 82;

